[Relative energy deficiency in sport: modern approaches to diagnostics, treatment and prevention]

In recent years, close attention has been paid to energy deficiency in professional athletes. More and more studies confirm the widespread prevalence of relative energy deficiency syndrome in sports and its relationship with various pathological conditions that lead to a decrease in the level of athletic performance. Nowadays the possibilities of early diagnosis and treatment of this syndrome are being carefully studied, and clinical protocols are being actively developed to facilitate the early detection of energy deficiency. The aim of the study was to summarize the modern data on the influence of the syndrome of relative energy deficiency in sports on the health and performance of athletes, as well as to consider effective methods for the diagnosis, treatment and prevention of this syndrome. Material and methods. The search was carried out using the Google Academy engine and electronic databases PubMed, MEDLINE, EMBASE, Scopus, Web of Science, eLIBRARY for the period from 2017 to 2021. For the search, we used keywords and their combinations: "relative energy deficit in sports", "female athlete triad", "menstrual dysfunction", "osteoporosis". Results. Based on our analysis, we can conclude that the syndrome of relative energy deficit in sports has a multicomponent negative effect on the athlete's organism and negatively affects his performance, well-being and sports results. Diagnosis of this condition is challenging due to the nonspecificity and variety of symptoms. Key diagnostic methods include physical examination, anamnesis gaining, dual energy X-ray absorptiometry, bioimpedance body composition analysis, and hormonal profile studies. Additional methods include: electrocardiography, study of the basal metabolic rate, hematological examination (hemoglobin, ferritin, etc.), determining the level of energy consumption using diaries of food and physical activity, determining blood vitamin level, etc. To facilitate the screening, diagnosis and follow-up of athletes, it is possible to use specially developed clinical protocols. Non-drug nutritional correction and optimal training plan are the main methods of treatment and prevention of energy deficiency. If this type of treatment is ineffective, hormone therapy should be considered. It is recommended to use transdermal estrogen therapy in combination with shortterm progestin therapy. In some cases, when very low bone mineral density or delayed fracture consolidation is detected, it is possible to use recombinant parathyroid hormone. Conclusion. Due to the relatively high prevalence of relative energy deficiency syndrome in athletes of both sexes and its long-term negative impact on athlete health and performance, further research is needed to improve the effectiveness of early diagnosis, prevention and treatment of pathological conditions associated with malnutrition.